
Here's a video from a bunch of years ago that makes me laugh. We do this thing...three seconds...where we have to try not to laugh for three seconds while the other person tickles us. It never fails, we end up cracking up.
Another thing that keeps our marriage laughing is mini marshmallows. We have a rule that if we're eating mini marshmallows we have to be throwing them at each other. We usually get one or two into our mouths and half the package ends up on the floor and we always laugh and laugh. Same goes for cheeseballs.
Although cheeseballs are way messier when we miss.